With 4.4 million copies sold and a wagon full of Grammy awards, there was little left for the O Brother, Where Art Thou? soundtrack to accomplish. After one year and ten weeks of release, the album added another accomplishment to its list, it reached Number One on the pop charts. O Brother sold 159,000 copies last week, according to SoundScan, and the collection of old time music performed by the likes of Emmylou Harris, Gillian Welch, Alison Krauss, Ralph Stanley and others bested the likes of Linkin Park, Ludacris, fellow Grammy-monger Alicia Keys and other, more mainstream fare. The album even fended off the first week sales of Brandy's Full Moon, which had to settle for Number Two with sales of 155,000. Last week's chart-topper, Alanis Morissette's Under Rug Swept, moved down to Number Three with sales of 120,000).

As for O Brother, the T Bone Burnett-produced soundtrack has managed unthinkable sales for an album filled with bluegrass, mountain music, gospel and blues. While the occasional bluegrass track ("The Ballad of Jed Clampitt," for instance) has crossed over onto the pop charts in the past, never before has an entire album ventured so deep into mainstream culture. Amid albums composed of songs about sex, dancing and dating, the O Brother formula of death, death and death isn't exactly the contemporary tonic of choice, yet the album has become something of a one-stop shopping item for those looking to stick their big toe into the rural roots music pool. "That's one reason why people like that disc -- if you're not a record collector, there's a real broad spectrum on the record," says Norman Blake, who chips in two songs on the soundtrack, as well as playing guitar. "And it's live, it's not just a reissue of old records."

And O Brother's ripples are being felt beyond it's soaring sales. Nickel Creek, a young bluegrass-minded trio, has seen its self-titled debut album lodge itself around Number 130 on the charts, with weekly sales around 10,000. The album is one week shy of topping 500,000 sales. Alison Krauss and Union Station, whose 1995 compilation Now That I've Found You was bluegrass' best-selling record prior to O Brother, have seen their latest album, New Favorite slide inside the Top 100, with sales over 400,000. Gillian Welch's latest album, Time (The Revelator), was released independently on her own Acony label; the album will likely top 100,000 units sold by the end of the month. And independent bluegrass label Doobie Shea Records claims that Union Station singer/guitarist Dan Tyminski, who won a Grammy for singing O Brother's "I Am a Man of Constant Sorrow" has seen orders for his solo album, Carry Me Across the Mountain, increase since his Grammy wins and performance. "There's no studio magic or tricks, you're listening to people standing and playing music together, which you don't hear as much anymore," Tyminski said last year. "And I'm seeing a lot of young people playing. From the musician perspective, it'll thrive for a long time, because there's so much young talent makings its mark right now. I hope when my kids are my age, its still going strong."

Little else of note happened on the charts. Jars of Clay's Eleventh Hour (Number Twenty-eight, 39,000 copies sold) and Natalie Imbruglia's White Lillies Island (Number Thirty-five, 33,000) were the only other newcomers in the Top Fifty. As for milestones, Ludacris' Word of Mouf sold another 80,000 copies to move past the 2 million mark.

O Brother's reign at the top of the charts might even last another week, as N.E.R.D.'s In Search of . . . looks to be the strongest newcomer, and one with little chance of reaching Number One.